Telephone-exchange system.



A. E. LUNDELL & F. A. STEARN. TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED OCT. '25. me.

1 $253,379., Patented Feb. 26, 1918.

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ALBEN E. LUNDELL, OF NEW YORK, N. 2., AND FRANKLIN A. STEABN, OF PATERSON, NEW JERSEY, ASSIGNORS TO WESTERN ELECTRIC COMPANY, INCORPORATED. OF NEW YORK, N. Y., A CORPGRATIGN OF NEW YORK.

TELEPHONE-EXCEANGE SYSTEM.

Application filed October 28, 1916.

T 0 all whom, it may concern:

Be it known that we, Annex E. LUNDELL and FRANKLIN A. STnAnN, citizens of the United States, residing at New York, in the county of Bronx and State of New York, and at Paterson, in the county of Passaic and State of New Jersey, respectively, have invented certain new and useful Iniprovements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone ex change systems.

The object of this invention is to provide means whereby a connecting operator is informed, by means of a tone in the receiver of her head set, that a calling subscriber desires her attention after a connection has been set up.

A feature of this invention is a relay arrangement by which such tone is connected to the operators receiver for a predetermined length of time.

The drawing shows portions of a circuit arrangement suitable for carrying out the invention.

It is thought the invention will best be understood from the following detailed description, reference being had to the accompanying drawing.

The invention is shown as applied to a semi-automatic telephone exchange system of the type disclosed in an application by A. E. Lundell, Serial No. 70, 159, filed January 5, 1915, only so much of this system being shown as is necessary to an understanding of the present invention. The invention is not restricted to this particular system, since it is obviously capable of arrangement for use with other systems.

When the subscriber at substation 1 desires a connection he removes his receiver from the hook, whereupon a line relay 2 is energized to causethe display of a line signal 3 in the well-known manner.

An operator, one of whose cord circuits is indicated at 0, upon observing the lighting of signal 3, inserts a plug 1 into a jack 5 associated with line signal 3. A circuit is then closed for answering supervisory relay 6 in the well-known manner. At the same time a cut-0E relay 7 and a sleeve relay 8 are energized over the sleeve contacts of plug 4: and jack 5.

Specification of Letters Patent.

Patented Feb. 26, 1918.

Serial No. 121934.

Relay 8, upon energization, completes a circuit from grounded battery, power magnet of listening key sequence switch 20, outer armature and front contact of relay 8 to ground for moving this sequence switch out of position 1 and into position 7.

vVhen the listening key sequence switch, certain contacts of which are indicated at 17, 18 and 19, arrives in position 7, a circuit is closed to the operators head set through sequence switch contacts 18, 19, and she may then converse with the calling subscriberand learn the number of the wanted line. She then sets up the desired connection as disclosed in the above mentioned application, the arrangement indicated in the drawing showing brushes 9 and 10 of an automatic switch by which such connection may be advanced.

if, after the listening key sequence switch has left'its listening-in position, the calling subscriber desires to attract the attention of the operator, he replaces his receiver on the hook for'an instant and then again removes it. Then the receiver is replaced on the hook, the supervisory relay 6 is deenergizcd and completes a circuit from grounded battery, left-hand winding of relay 11, armature and back contact of relay 6, lamp 12, to ground at the inner armature and front contact of relay 8. Relay 11 is energized and completes a locking circuit for itself from grounded battery, right-hand winding of relay 11, its right-hand armature and front cont-act. listening key sequence switch contact 17, closed in positions 8 to 18, to ground at the armature and back contact of slow release relay 13. #Vhen the receiver is again removed from the hook supervisory relay 6 is again energized, and slow release relay 1% is energized over a circuit from, grounded battery, right-hand winding of relay let, left-hand armature and front contact of relay 11, armature and front contact of relay 6, lamp 12, to ground at the armature and front contact of relay 8; Relay 14- attracts its armatures and completes a cir-' cuit by which a tone is induced into the op erators receiver, such circuit being from grounded battery, interrupter 15, primary winding of coil 16, to ground atthe righthand armature and front contact of relay l4. Relay 14 at its left-hand armature completes a circuit from grounded battery, left hand armature and front contact of relay 14, winding of relay 13 and left-hand winding of relay 14, to ground. Relay 13 attracts its armatures and at its left-hand armature opens the locking circuit of relay 11, which deenergizes, thereby opening the circuit through the right-hand winding of relay 1%. In addition, relay 13 at its lefthand armature shunts out the left-hand winding of relay 14, the energizing circuit of relay 13 now being from grounded battery, left-hand armature and front contact of relay 1a, winding of relay 13, to ground at the left-hand armature and front contact. The circuits of both windings of relay 1a are now open and after a time it releases its a matures. When the left-hand armature of relay let is retracted, the energizing circuit of relay 13 is broken and after a time it retracts its armatures, breaking at its right-hand armature the circuit over which the tone was produced in the operators head set. It will be noted that the tone will begin when relay 1% is energized and continues until relay 13 is deenergized. The relays are now all in the condition in which they were when the connection was first established.

The supervisory lamp 12- is lighted during the time in which relay 11 isenergized and aids the operator in determining which subscriber desires her attention.

At conclusion of conversation, the call ing subscriber replaces his receiver and causes the permanent deenergization of relay S. Supervisory lamp 12 is lighted over a circuit from grounded battery, left-hand winding of relay 11, armature and back con tact of relay 6, lamp 12, and inner armature and front contact of relay 8, to ground. Be lay 11 is energized but relay 14: does not energize since relay 6 is not again energized. When the operator removes the plug 4 from the jaclr 5, relay 8 is de'energized and the supervisory lamp 12 is extinguished.

hat is claimed is:

1. in a telephone exchange system, calling and called lines, an operators circuit for interconnecting said lines, an operators receiver, means for connecting said operators receiver to a calling line, means to audi'oly inform said operator that the calling subscriber desires her attention after a connection has been established, and means for applying said informing means for a predetermined length oii time.

2. in a telephone exchange system, calling and called lin s, an operators circuit for interconnecting said lines including a plurality oi relays, an operators receiver,

. ieans tor audibly informing said operator that a calling subscriber desires her attention after a connection has been established, the duration of application of said informing means being dependent on the time required for the release of certain of said relays.

3. In a telephone exchange system, calling and called lines, an operatofs circuit for interconnecting said lines including an answering supervisory relay, a combination of relays, an operators receiver, means for connecting said operators receiver with a calling line, means to audibly inform said operator that a calling subscriber desires her attention after a connection has been estahlisned, a circuit arrangement for successively encrgizirg said combination of relays upon the de'energization of said supervisory relay, means for causing the successive deenergization of said combination of relays upon reenergization of said supervisory relay, said informing means being applied to said operators receiver during the actuation and release of said combination of relays.

4. In a telephone exchange system, calling and called lines, an operators circuit for interconnecting said lines, an operators receiver, means for connecting said operators receiver to a calling line, means to audibly inform said operator that a calling subscriber desires her attention after a conuection has been established, and means for preventing the application of said audible informing means when said operator first establishes a connection to a called line.

In a telephone exchange system, calling and called lines, an operators circuit for interconnecting said lines including an answering supervisory rel y, an operators receiver, a relay arranged to be energized in certain stages of operation of said system upon the deenergization oi said supervisory relay, a pair of s1ow-rolease relays, means to cause current variations in said receiver to produce a tone audible to said operator, the application of said means being controlled at a front contact of either of said slowrelease relays, means for successively energizing said slow-release relays, and means controlled by the interaction of said relays for restoring all of said relays to a normal condition.

In witness whereof, we hereunto subscribe our names this 25th day of October, A. D. 1916.

ALBEN E. LUNDELL. FRANKLIN A. STEARN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Baton.

Washington, D. C. 

